1. Field of the Invention
The present invention relates to improved power tools.
2. Description of the Related Art
Japanese Laid-open Patent Publication Nos. 7-314344 and No. 10-180643 describe power tools that control the drive source (e.g. a motor) for driving the tool bit in order to improve and stabilize the tightening operation in certain predetermined conditions. This type of power tool has a setting switch disposed on the surface of the housing of the tool and the setting switch permits the operator to set the driving condition. Thus, the drive source can be controlled according to a predetermined condition that is set using the setting switch.
Presently, impact power tools are often used for a variety of operations. For example, a tightening tool adapted to tightening fastening devices (e.g., bolts, nuts, screws, etc.) can be used for a temporary tightening operation, a disassembly operation, and a repairing operation in addition to the usual tightening operation. However, known power tools do not include a setting function that permits the operator to set appropriate condition for these types of operations. Therefore, known power tools cannot be effectively used for such operations.
In addition, because the switch for setting the driving condition is disposed on the surface of the housing, the driving conditions can be freely changed by a variety of people. Thus, the known power tools do not permit the driving conditions to be changed only by an authorized person.
Further, known power tools do not provide means for setting maintenance conditions. Thus, known power tools may be utilized beyond the expected lifetime of one or more components of the power tool and the power tool may break down at an inappropriate time. Thus, a long felt need exists to provide power tools that can provide accurate actual use records and promptly inform the operator if maintenance is recommended or required.
In addition, U.S. Pat. No. 5,289,885 describes an impact wrench that can be used to firmly tighten a threaded object, such as a bolt or a nut. In this type of tightening tool, the torque that is generated depends upon the number of times and the frequency at which the hammer impacts or strikes an anvil. In the '885 patent, a microphone is utilized to detect the impact sound of the hammer striking the anvil. When the number of the impacts by the hammer on the anvil reaches a predetermined number, the motor stops rotating the hammer. Thus, an appropriate amount of torque is applied to the threaded object by stopping the tightening operation when the predetermined number of impacts has been reached.